<!DOCTYPE html>
<html>
<head lang="en">
    <meta charset="UTF-8">
    <title>统计考试科目的成绩</title>
</head>
<body>
<input name="btn" type="button" value="统计考试成绩" onclick="count(prompt('请输入考试科目数量'));" />
<script type="text/javascript">
    function count(num){
       
    }

</script>
</body>
</html>